The invention relates to a method for measuring the cooling curves of molten masses (melts) and/or the heating curves of melt samples by an optical fiber. For this measurement an immersion end of the optical fiber having an at least partially free surface is surrounded with a spacing by a temperature-resistant sample-receiving chamber, such that the optical fiber is immersed with its immersion end in the melt. In this way, a sample is formed in the sample-receiving chamber, and the sample-receiving chamber with the sample and the optical fiber is thereafter pulled out of the molten metal. The cooling curve of the sample and/or, after previous solidification of the sample, the temperature profile during heating is measured with reference to a signal obtained by the optical fiber and forwarded to a measurement device. In addition, the invention relates to a corresponding device as well as to its use. Here, melts are understood to include both melts of pure metals, such as iron, copper, or steel, or alloys, as well as cryolite melts, molten salts, or molten glass.
Temperature measurement methods and devices, in which liquid temperatures are measured with the aid of optical fibers at high temperature, are known from European Patent EP 646 778 B1, among others. Additional devices are known from U.S. Pat. No. 4,355,907. There, an immersion sensor is described, with which a sample of a molten metal is taken. The sample thereby adheres in a hollow space. A graphite plate is arranged between the hollow space and the optical fiber receiving the measurement values.
A sample vessel, into which molten metal is poured and in which the temperature of the molten metal is then measured by means of an optical fiber, is known from German published patent application DE 36 31 645 A1. Other devices for measuring the temperature in molten metals are known from Japanese published patent applications JP 62-185129 and JP 62-185130. In addition, methods for measuring the melting-point temperature in a smelting crucible with the aid of optical radiation are known from U.S. Pat. No. 6,106,150 and U.S. Pat. No. 6,004,031, or from European published patent application EP 802 401 A1.